Over the xmas hols (I'm a money grabbing student), I've been following the tabata protocol on a rowing machine (5 sessions a week, 1 of which is 1/2 hour UT2 then 2 mins of intervals, warming up with a 7 min negative split 2k followed by ~5mins rest before each session) with some weights on top. I've seen definite improvement in the distances I'm putting out, and as far as I know the rest of my rowing crew have mainly been doing long UT2 sessions, so I'll be able to compare our performances in a few weeks. Not sure how tabata's shape up with other forms of HIIT though, but I know that doing it on a rower sucks balls, although the suckitude seems to be instant then I generally don't feel it the next day.

A 1:1 work to rest ratio (with a prolonged time period, i.e. - longer than 30 seconds) showed more improvement in all endurance relevant parameters over a 30 s work to 4.5 minutes rest protocol in this 10 week study of runners:

Update: The HIIT on a bike continues, though with a few modifications. I've kept the ratio at rest .60, work .30, but with a ten minute warm up instead of five, and taking the resistance down one notch to 6 (out of 8). I'm hoping these two changes will help with the stiffness in my back and knees.

Work-wise, it's still a killer, but I can manage and feel good. I think I can already feel some of the benefits. For example, I'm getting through rounds better, and only this morning I amazed myself after dropping my son off at school, when I guy drove past me, stuck his finger up and said something through the window - exactly what was unclear, but the last word looked like 'you'. Keen to discover why he should wish to address me thus, I set off in pursuit, chasing his car on foot for a good 300+ metres to the next intersection. Luckily for him (and me, I admit), the light changed before I got there, and he drove off.

I ran quicker, through unplowed snow, than I've done since my early twenties, I when I got there, I wasn't breathing hard at all.